Effects and Mechanisms of Non-Antibiotic Emerging Contaminants on Fish Gut Microbiota
Non-antibiotic emerging contaminants (ECs) pose a growing threat to aquatic organisms, particularly fish, yet their impact on gut microbiota remains inadequately characterized. This systematic review synthesizes current evidence on the effects and mechanisms of non-antibiotic pharmaceuticals, pesticides, per- and polyfluoroalkyl substances (PFAS), nanomaterials, and microplastics on fish gut microbiota. Exposure to these ECs directly alters microbial composition and diversity, while indirectly disrupting host metabolism and immune function, leading to significant health impairments. Notably, EC exposure induces dysregulation of key factors such as lipopolysaccharide (LPS), compromising intestinal barrier integrity. Concurrently, gut microbiota can metabolically transform certain ECs into derivatives, establishing a complex pollutant-microbiota-host interaction network. The gut microbiota mediates EC-induced neurotoxicity, immune dysfunction, and metabolic disorders through signaling pathways such as TLR/NF-κB and metabolic homeostasis regulation. Current research predominantly addresses short-term exposure effects, leaving long-term low-dose impacts and transgenerational mechanisms poorly understood. Future investigations should employ multi-generational exposure and microbiota transplantation to elucidate gut microbiota-mediated toxicity mechanisms under non-antibiotic EC stress. This review underscores the urgent need for comprehensive risk assessment and regulatory frameworks targeting non-antibiotic ECs in aquatic environments.